Frog wrote:

Not a plausible claim, to anyone who recalls the situation at the top of the WTC on those days. The incredible heat and smoke from an entire jetliner full of fuel a hundred feet below would make helicopter operations impossible. Trying to land on the roof under those circumstances would be suicide. Helicopters circled, but they could not approach.

That was the initial perception. The NY Times had a report yesterday about a pilot of one of the police choppers who described his futile rescue attempt -- he was on the scene within ten minutes of the crash. The pilot said the smoke was blowing away from Tower 1 (the first hit) so there was a fair sized refuge for people to stand in any had accessed the roof. A thicket of antennas would have prevented landing but the pilot said there was a hoist onboard with a 200 foot cable capable of picking up people. A colleague was ready to descend to the roof to assist. Nobody came to the roof. Another chopper hovered nearby to do the same. Other choppers were on their way from Long Island but flights were cancelled when it was reported nobody was on the roof. The pilot said it was possible that at least a dozen or so people could have been rescued before the collapse. The pilot said at the 1993 bombing a cop was lowered to cut away a wad of antennas so roof pickups could be made, but that was too risky on 911. The Times report said that only Los Angeles allows chopper rescue from high rise buildings. Most fire departments believe chopper rescue is too high risk and that exit by stairway is far safer. But in the light of WTC collapse fire departments are reviewing that prohibition. The NY Fire Department, like many FDs, has no choppers, and sees police choppers as scenewhores. Not as bad as Sir Rudy and the Fire Commish but close.